(Metrics that Matter is a regular offseason feature that examines some aspect of fantasy through a microscope to dive into the finer details.)

Alvin Kamara was absolutely ridiculous in 2017. He won the AP Offensive Rookie of the Year Award, he was our second-highest-graded running back (behind Todd Gurley), and was also probably the best fantasy draft pick you could have made. Still, just highlighting these accomplishments feels like an understatement to what was arguably one of the most efficient running back seasons of all time.

Since the NFL merger (1970) there have been 2,173 instances of a running back totaling at least 100 carries in a single season. Of those seasons, Kamara’s 2017 season ranks fourth-best in yards per carry (6.07), behind only Mercury Morris (1973), Jamaal Charles (2010), and Barry Sanders (1997).

However, as I’ve written about in other articles, I loathe yards per carry as an efficiency statistic. Mainly, it fails to divorce offensive line play from running back play. Two other running back efficiency metrics — yards after contact and missed tackles forced — add more context and give a more accurate representation of a runner’s ability with the ball in his hands, independent of the blocking in front of him.

Well, the Saints ranked just 18th in run-blocking grade, and Kamara led the league in yards after contact per attempt and missed tackles forced per touch (min. 175 touches). Again, this feels like an understatement. Looking at all 356 running back seasons (min. 175 touches) during the PFF era (2007-2017), Kamara’s 2017 season ranks third-best in yards after contact per attempt and second-best in missed tackles forced per touch.

Factoring in both stats into one chart (where the farther top-right a player finishes, the better or more efficient their season was), it’s clear Kamara stands out yet again.

From more of a fantasy perspective, this was, again, arguably the most efficient running back season of all-time. Of the 2,173 instances of a running back totaling at least 100 carries in a single season since the merger, Kamara ranks best in fantasy points per touch and second-best in yards per touch.

Since the NFL merger (1970) there have been 2,173 instances of a running back totaling at least 100 carries in a single season. Of those seasons, Alvin Kamara’s 2017 season ranks best in fantasy points per touch and second-best in yards per touch. pic.twitter.com/qMh2W2BK1B

What does this mean for fantasy?

At a certain point, these ridiculously high efficiency numbers will make someone like me nervous. How likely are these numbers to repeat? Will Kamara continue to put up all-time great numbers each year? Probably not – typically, hyper-efficient seasons regress much closer to the league-average in the following season.

As I’ve written about for a number of years now, raw snaps and volume are more important for the running back position than any other position in fantasy, and Kamara will likely still be stuck in a timeshare with Mark Ingram. While Kamara’s production was other-worldly, his volume was closer to the fringe-RB1-range.

Following Adrian Peterson‘s trade to Arizona, Kamara averaged only 13.9 expected fantasy points per game (13th-most among running backs), while Ingram averaged 15.1 (seventh-most). Not only was Kamara our most efficient player this season, scoring 98.6 fantasy points over his expectation, he was also our single most efficient player this past decade. Touchdowns, specifically, are fairly random, and he scored 13, while the data suggest a purely average running back would have scored only 5.4 on similar volume (based on a 10-year average looking at each carry by distance from the end zone and each target by depth of target and distance from the end zone).

So, is a regression coming? I think it is, and I’m concerned, but maybe not as concerned as other fantasy analysts.

Saints head coach Sean Payton has long made a living by getting the most of his running backs. In the PFF era, nine of the top-30 running back seasons by fantasy points per snap (min. 350 snaps) have come from a Saints running back, while no other team makes the list more than twice.

Current ADP has Kamara going off the board as the fifth player overall in PPR leagues. Based on natural regression and a capped upside so long as Ingram stays healthy, I think that’s too high. At the same time, he showed his upside is other-worldly, and I’m confident Payton will continue to make the most of his abilities. While I think fifth overall is too high, I’d be happy to grab Kamara in the late first or early second if he manages to fall there.